<div class="bg">
  <div class="snow snow-background"></div>
  <div class="snow snow-background layered"></div>
  <div class="snow snow-middleground"></div>
  <div class="snow snow-middleground layered"></div>
  <div class="snow snow-foreground"></div>
  <div class="snow snow-foreground layered"></div>
</div>